Method and an installation for collecting from and detecting a fresh water spring at sea

A method of collecting fresh water from a spring at sea, in which method a reservoir suitable for trapping fresh water is immersed with its open concave side facing downwards, the circumference of the bottom end of said reservoir surrounding the fresh water resurgence, said method being characterized in that the following steps are performed:

• 1) lowering said resrvoir in a folded state, said reservoir being constitued by a compartmentalized, double walled, flexible envelope;
• 2) deploying said reservoir, which takes up a spherical-cap shape under the pressure of the water that fills it;
• 3) securing the bottom end of said reservoir to the bottom of the sea in a leakproof manner by making the circumference of said bottom end follow the relief of the sea bottom;
• 4) injecting a concrete slurry into the compartments of said double-walled envelope, said concrete slurry having specific gravity close to 1 so that the double-walled envelope keeps the shape of a spherical cap after being filled with concrete;
• and
• 5) collecting the fresh water by means of a pipe opening out at its first end into said reservoir, and at its second end into a zone of land situated below sea level.